Will Portable Generators Run a Heat Pump?

  • By: Umer.A
  • Date: October 10, 2021
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Portable generators are not designed to power large systems like electric furnaces or heat pumps. But some portable generators are capable of running mid-sized heat pumps. This will depend highly on the wattages of the heat pump system and portable generator unit.

In this guide, we’ll find out whether portable generators can power heat pumps or not.

How Many Watts Are Needed to Run a Heat Pump?

Heat pumps need over 15,000W to operate properly. This number is enormous, especially if you compare it with a regular heat pump on oil or gas (2500W). However, you can easily calculate the among of watts your heat pump needs to run by multiplying its voltage with amps.

The numbers for amps and volts are available in the specs of the panel box of your heat pump. But the answer that you will get from the formula is only going to be an estimate. This is because a heat pump doesn’t use the same amps and volts mentioned on the panel box.

If you are looking for a more accurate estimate, ask any service tech pro to do it. Most 3-ton heat pumps available on the market need 7200 surge watts and 5400 running watts to operate properly on a generator.

So, you will need an 8000W unit for this, and that to only runs the generator for the heat pump only and not any other appliances or devices (which will not be the case). So, you will need a generator with some heavy wattage rating.

What is the Ideal Generator Wattage Rating for Powering a Heat Pump?

As heat pumps typically need over 15,000W, portable generators are not the right option to power them. You will need a standby generator for homes to power such a heat pump system. This generator unit will come with a wattage rating of 17,000W, and it’s a good option to work with your heat pump.

Your generator should have more wattage rating than your heat pump system to power it properly. And you also have to consider the surge wattage rating of the appliances, particularly your heat pump, which will be significantly higher than its running wattage rating.

You also need to keep in mind that a more significant generator will always cost you more fuel. So, your energy costs will remain high for as long as you will be using that generator.

Can a Portable Generator Run a Mini Heat Pump?

Mini heat pumps with ductless design are also pretty powerful systems, but they come with lesser wattage ratings. But not all of the ductless systems consume lower amounts of wattage. Instead, some of them are pretty higher than others. Therefore, when buying a ductless-split heat pump, you need to check that system’s wattage rating carefully.

The better option to go for is a mini-split system as they are great for trailer homes and can be powered by generators. The mini-split heat pump systems can efficiently operate on a portable generator’s power supply. But rest assured they are only useful in case of emergencies.

Some people want to use these generator units as their primary and secondary sources of power supply. But for such heat pump systems, these generator units should only be used as backups and nothing more.

For example, a 1.5 ductless mini-split heat pump system will need over 5000 surge watts and around 3950 running watts on a 20-amp power supply.

Running a Ductless Mini-Split Heat Pump with your Portable Generator

You need to follow a few steps when connecting your portable generator with your mini-split heat pump system.

  • You need to look for that transfer switch directly attached to the heat pump circuit. If there is no transfer switch, you will have to contact an electrician to install a transfer switch
  • The next step is to rewire the system by cutting the wire going through the furnace into its circuit breaker. You will have to install an outlet for the wires to run between the circuit breaker and the furnace of the heat pump. Make sure to spare an outlet for the generator plug.
  • After that, you will have to install that generator plug on the inside of the furnace. Now plug that furnace in and reset your breaker. This will allow you to check if your furnace is still working as it is supposed to.
  • Ensure you don’t put your generator plug right next to the furnace or anywhere close just for convenience. You need to place it in a safe location because it emits CO (carbon monoxide), and this gas shouldn’t be trapped inside your home or within any of those confined spaces.

What generator size will work for a 3-ton heat pump?

A three-ton heat pump is rated for 7200 starting watts and 5400 running watts. And if you are planning to run more appliances on your generator, you will need a generator with over a 10,000 wattage rating.

Are portable generators capable enough to power a heat pump?

Portable generators don’t come with the wattage rating to supply enough power to start a heat pump. Heat pumps are pretty large systems, and they do need plenty of starting power. If you own a portable generator, you need to go for a ductless mini-split heat pump to work with it, but only if the wattage ratings match.

My heat pump doesn’t come with a transfer switch; what should I do?

If your heat pump doesn’t feature a transfer switch, you need to install it by an experienced electrician. Ensure that you don’t do it on your own or end up damaging your heat pump for good.

Can a 10,000W generator power central air in my house?

Yes, a 10,000W generator has got what it takes to run central air in your house. Anything below this wattage rating will not work at all to power the whole air system in your home.


Portable generators don’t have what it takes to power a heat pump. These heat pumps are too massive, and they need plenty of surge watts to start working. Instead, you can go for mini-split heat pumps to work with your portable generators. But be sure to check the wattage ratings of your unit and the system.